The invention relates to an oil film bearing for use on the conical neck of a rolling mill roll, the roll neck being provided with a conical bush disposed to rotate along with the rolling mill roll, the bush, in turn, being fitted to a fixed cylindrical bearing bush inserted in the roll chock, in which case the high-pressure oil film building up between the fixed and rotating bushes effects lubrication of the transition zone between the conical roll neck and the rotating bearing bush by way of supply bores machined radially into the rotating bush, in that the oil is forced to flow into oil grooves distributed on the circumference of the rotating bush and extending in the axial direction of the bush.
To simplify and facilitate removal of the rotating bush from the roll neck where such oil film bearings are used, the interference fit between the conical surfaces is generally maintained relatively moderate, in other words, less tight. Therefore, a certain amount of relative movement may occur between the rotating bearing bush and the rotating roll neck in operation under load and, unless proper lubrication is provided between the fitted conical surfaces, this will result in contact corrosion by the adhesive friction between the roll neck and the bush, ultimately leading to heavy friction wear and to the so-called "black spots". In serious cases, the rotating bearing bush and/or the roll neck may actually become permanently damaged.
A known method of preventing these detrimental phenomena (DE-OS 2 843 658) is to add secondary oil grooves to the existing primary oil grooves and to interconnect these grooves by connecting grooves, to form several separate networks of grooves distributed on the circumference of the conical bushes, which will successively receive high-pressure oil through the supply bores as each of these networks of grooves rotates through the load zone of the bearing. The object is to improve lubrication by increasing the oil supply to the transition zone between the roll neck and the rotating bearing bush of the oil film bearing.
Apart from the very high costs involved in manufacturing such networks of grooves, a great number of partial surfaces on the bush and the roll neck still lack reliable lubrication despite the more extensive distribution of oil through the primary, secondary and interconnecting grooves, since lubrication is essentially limited to the areas of the actual groove networks, whilst the areas between the networks will, at most, receive a slight sweep of straying and not selectively controllable creep oil.
Thus, the object of the invention is to avoid the foregoing disadvantages and to dispose the oil grooves in the rotating conical bearing bush in a manner to permit comprehensive oil distribution for prevention of contact corrosion between the conical roll neck and the bush fitted thereto.